Abstract

<p>The few previous studies of precipitation isotopes (δ<sup>18</sup>O and δD) in Indonesia, based on low spatial resolution observation datasets, have found several types of patterns in their seasonal variabilities. This study conducted high spatial resolution rainfall sampling and investigated the temporal characteristics of precipitation isotope in Indonesia. Rainfall samples were collected weekly from 33 stations in Indonesia. Cluster analysis showed that Indonesia could be divided into four types based on the seasonal variability of the precipitation of δ<sup>18</sup>O. The majority of stations showed seasonal patterns in the variability of δ<sup>18</sup>O, characterized by high values in the dry season (July–October) as type 1. Type 2 also showed one peak of high δ<sup>18</sup>O but in the longer period (June–November) was similar to type 1 stations. A region of Northwest Indonesia, comprising North and Central Sumatra and western Borneo, was identified as type 3, having two peaks of high δ<sup>18</sup>O values in January–February and May–August. Another pattern of variability was the anti-monsoonal type, indicated by low δ<sup>18</sup>O in May–July found in east part of Indonesia. Asia-Australia monsoon regime was the main factor that controls seasonal δ<sup>18</sup>O variability. This research showed that stable isotope in precipitation could correspond to precipitation climatology in Indonesia.</p>

Journal

Hydrological Research Letters

Hydrological Research Letters 11(2), 92-98, 2017

Japan Society of Hydrology and Water Resources (JSHWR) / Japanese Association of Groundwater Hydrology (JAGH) / Japanese Association of Hydrological Sciences (JAHS) / Japanese Society of Physical Hydrology (JSPH)